In the past, cleaning hydrocarbons from liquids and solid surfaces has been difficult. For example, cleaning hydrocarbons coating or contaminating other materials has typically entailed the addition of surfactants to disperse the hydrocarbons followed by dilution in a carrier solution such as water. Other methods, for example cleaning oil spills at sea and/or on land oil spills, have used materials such as sawdust, peat or similar organic materials that adsorb the hydrocarbons creating a mass which can be collected and transported to land fill sites. In these cases, the handling of the cleaning solutions or absorbing materials is difficult and requires that the cleaning solutions and absorbing materials also be handled and disposed of at an alternative site.
In the more specific case of drill cuttings, the disposal of hydrocarbon contaminated drill cuttings (hereinafter “drill cuttings”) has been a significant issue for drill site operators. For example, in a typical drilled well in the oil industry, upwards of 100 m3 of drill cuttings may be produced from a single well. Typical drill cuttings may also contain a variety of contaminants including hydrocarbons, salts, metals, soaps and other agents that may have been added to the drilling fluid to assist in the drilling and hydrocarbon recovery processes or become mixed with the drilling fluid from the formation.
In a typical drilling process, recovered and dried drill cuttings may include approximately 15% (w/w) hydrocarbon contaminants that may range in viscosity from highly viscous bitumens to less viscous lighter fractions.
Acceptable methods of disposal of drill cuttings are usually dictated by various jurisdictional regulations and will usually require that the drill cuttings are properly remediated into the local soil or alternatively, removed to a landfill site. Current methods for adsorbing or absorbing free oil prior to remediation include mixing the drill cuttings with sawdust or peat moss. Typically, volume ratios of 2:1 for sawdust (sawdust/drill cuttings) and 1.5:1 for peat moss (peat moss/drill cuttings) have been used to effectively stabilize contaminated drill cuttings. However, using such absorbents creates a sizable volume of waste to be transported to and contained at a disposal site.
Moreover, such disposal methods may lead to certain environmental contamination as the various contaminants may ultimately leach into the local groundwater, particularly as materials such as sawdust or peat decomposes. As well, as noted, the cost of transportation of drill cuttings to a landfill and/or the cost of soil remediation is significant.
As a result, there has been a need for effective disposal methods wherein oil contaminated surfaces can be effectively and efficiently cleaned in a manner that provides both effective cleaning and simplified disposal of the oil contaminant. In the particular case of drill currings, there has been a need for method wherein the drill cuttings are either stabilized or disposed of in a manner that meets environmental regulations, that provides an effective method of minimizing environmental contamination by waste drill cuttings, that does not increase the overall cost of disposing of drilling cuttings and that may provide a way of effectively recovering spilt hydrocarbons. More specifically, there has been a need for a process to stabilize drilling cuttings and/or a disposal method in which drill cuttings provide a useful product in other applications such as a road wherein the contaminants may be encapsulated or incorporated with other materials to reduce the likelihood of the contaminants leaching to the environment as well as providing useful and beneficial properties in those other applications.
In addition, recovery of spilt hydrocarbons from other contaminated surfaces has also been problematic due to the cost and complexity of various hydrocarbon recovery processes. As a result, there has been a need for new methods of recovering spilt hydrocarbons from a variety of surfaces including both liquid and solid surfaces where the recovered hydrocarbons can in some applications be recycled.